FIG. 1 depicts a portion of a conventional hard bias structure 10 that may be used in a conventional read transducer or other device. Such a conventional read transducer would typically include a conventional shield, a conventional insulator, a read sensor, conventional leads, conventional insulator, and a conventional top shield in addition to the hard bias structure. The conventional had bias structure 10 is typically used to bias the read sensor.
The conventional hard bias structure 10 includes a conventional hard bias layer 20 and a conventional seed layer 18 that may reside on a conventional insulator 14. The conventional seed layer 18 is formed prior to the conventional hard bias layer 20. The seed layer 18 is desired to provide a surface suitable for growth of the conventional hard bias layer 20. The conventional seed layer 18 is typically composed of a layer of Cr, CrV, or CrTi. Alternatively, the conventional seed layer 18 may be a bilayer including a Ta underlayer (not separately shown) and a W layer (not separately shown) between the conventional hard bias layer 20 and the Ta underlayer. The conventional seed layer 18 is typically formed by sputtering the Cr, CrV, CrTi, W and/or Ta in a Xe gas plasma.
The conventional magnetic hard bias layer 20 is formed on the conventional seed layer 18 by sputtering the material for the conventional hard bias layer 20 on the conventional seed layer 18. In conventional methods, the material such as CoPt, is sputtered in a Xe gas onto the conventional seed layer 18.
The conventional hard bias structure 10 may be used to magnetically bias the read sensor. For example, the conventional magnetic hard bias structure 10 may ensure that the free layer (not shown in FIG. 1) is stable and single domain. To ensure the stability of the read sensor, the conventional magnetic hard bias structure 10 should not be affected by external magnetic fields, for example from the recording media or write transducer. The conventional hard bias layers 20 are desired to have a high remanence magnetization, a large coercivity, and be thermally stable.
Although the conventional hard bias structure 10 functions, one of ordinary skill in the art will recognize that there are drawbacks. In particular, the magnetization of the conventional hard bias layer 20 may be disturbed during operation of the conventional magnetic read transducer. As a result, the free layer (not shown in FIG. 1) may be destabilized. Consequently, performance of the conventional magnetic transducer may be adversely affected.
Accordingly, what is needed is a system and method for providing an improved hard bias structure.